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M51 single nighter, TEC140.

ollypenrice

By ollypenrice
in Imaging - Deep Sky

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ollypenrice

ollypenrice

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A super run last night, with decent transparency and superb seeing. Our guest Dave fancied M51 so we collected 12x15mins luminance, 8x10mins colour and 2x20 mins Ha. TEC I40 Apo, Atik 460 mono, Baader filters. Small aperture and small pixels don't work too badly together, it seems. The Mesu's guide trace was ludicrously good in the excellent seeing.

5ab13db37ccd6_M51TECHaLRGB7HRSweb.thumb.jpg.8ae7195e7f94169b8f9a78a2c287864e.jpg

I could've cheated and slipped in some of the ODK14 data I did with Yves a few years ago but didn't! That'll be for another day!

Olly

 

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rl

rl

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Spectacular. I can't decide whether to be inspired or just bin all my kit facing up to the sad truth I will never get results like that......

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ollypenrice

ollypenrice

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2 minutes ago, cfpendock said:

About as good as it gets.  Is it cropped at all, or is this the normal image size for the TEC + Atik 460? 

Chris

It's cropped, Chris. On the net I wanted to show the galaxy at close to 100%. In TIFF format it holds up quite well at full size but a second equivalent night's data would be needed to take it all the way there. Diminishing returns, of course.

Olly

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ollypenrice

ollypenrice

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50 minutes ago, swag72 said:

Very nice - Soft and colourful processing .... Just enough of the outer shell without it being forced :) 

Thanks, S. I really do have a lot of M51 data but I can't say that I have found hard evidence of much more than you see here. That doesn't mean it doesn't exist but if I pushed my data beyond this point I'd be painting. Others may have better data, of course.

Olly

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steppenwolf

steppenwolf

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Very nice indeed, Olly. I am a little at a loss over your 15 minute exposures in luminance though as I found that with my Esprit 150 ED and QSI 683, my core on this object was destroyed at this exposure length!! I demand an explanation ............ :D

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ollypenrice

ollypenrice

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1 hour ago, steppenwolf said:

Very nice indeed, Olly. I am a little at a loss over your 15 minute exposures in luminance though as I found that with my Esprit 150 ED and QSI 683, my core on this object was destroyed at this exposure length!! I demand an explanation ............ :D

Dear boy, your wish is my command! A small circle of inner core was indeed burned out. After constructing the main image we went back to the RGB-only data and did a soft stretch in which the core was still OK, then subjected it to rather brutal unsharp masking to wrench out some contrasts. This wasn't pretty but we only wanted the tiny inner core, which we then applied as luminance over the tiny burned out original core, discarding the rest. Photoshop layers a go-go.

It might have been better to shoot a few short L subs but I often rescue saturated bits of luminance by creating a luminance from the shorter RGB subs I usually shoot.

Olly

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steppenwolf

steppenwolf

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1 hour ago, ollypenrice said:

Dear boy, your wish is my command! A small circle of inner core was indeed burned out. After constructing the main image we went back to the RGB-only data and did a soft stretch in which the core was still OK, then subjected it to rather brutal unsharp masking to wrench out some contrasts. This wasn't pretty but we only wanted the tiny inner core, which we then applied as luminance over the tiny burned out original core, discarding the rest. Photoshop layers a go-go.

It might have been better to shoot a few short L subs but I often rescue saturated bits of luminance by creating a luminance from the shorter RGB subs I usually shoot.

Good answer! :D Thanks for the explanation, Olly - I am relieved to learn that there was some subtle 'skulduggery' involved in restoring the core. :eek:

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tomato

tomato

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Another exceptional image, and all in one night, wow!

Interesting observation on the Mesu guiding. I was imaging the same subject last night with admittedly a rather rough and ready polar alignment, (took me an hour to sync the mount due to an out of alignment Telrad, but that's another story), guiding would be great for up to 60 seconds or so then one or both axies would shoot off randomly without warning for one or two exposure cycles  then settle right back down again. Not seen this effect so pronounced before. I guess a turbulent atmosphere will do that?

 

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Sunshine

Sunshine

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I have been gathering knowledge of refractors in preparation for my next scope which will be a refractor, one i intend to keep for life, originally, a Televue or Tak in the 120 range was where had my heart set.

But now, after reading further into TEC i believe from a price vs performance point of view they are definitely winners!

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ollypenrice

ollypenrice

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4 hours ago, tomato said:

Another exceptional image, and all in one night, wow!

Interesting observation on the Mesu guiding. I was imaging the same subject last night with admittedly a rather rough and ready polar alignment, (took me an hour to sync the mount due to an out of alignment Telrad, but that's another story), guiding would be great for up to 60 seconds or so then one or both axies would shoot off randomly without warning for one or two exposure cycles  then settle right back down again. Not seen this effect so pronounced before. I guess a turbulent atmosphere will do that?

 

Honestly, I don't think so. I think your problem lies elsewhere. If the guide corrections are in the right direction and of about the right magnitiude they may overshoot but they will never drive the mount in the wrong direction on a second input. You might expect a see-saw guide trace of over-corrections but not a swipe on the elbow sending your pen across the page, so to speak.

All that ever happens to my Mesus is that in times of high turbulence (and we do get them) the RMS values rise but the underlying behaviour remains as usual. I suspect you have a SiTech problem. You won't be the first! I run the old ArgoNavis/Stellarcat versions of the mount and never have any bother.

Have you considered Lucas Mesu's adaptation of the Losmandy polarscope? It's very good. Being observatory based I don't use mine but one of our guests says it takes him less than a minute to polar align his mobile Mesu using this system. It's 100% software free and so can be expected to work! :evil4:

Olly

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